Removable switchgear interlocking control



Feb. 6, 1951 c. D. EICHELBERGER 2,540,314

REMOVABLE SWITCHGEAR INTERLOCKING CONTROL Filed June 18, 1948 Inventor:

Charles D. Eicl'weiloergefi His Attorney.

Patented Feb. 6, 1951 REMOVABLE SWITCHGEAR TERLOCKING CONTROL Charles D.. Eichelberger, Ridley..Park,.Pa., assignorto General Electric. Company, ...a. corporation of New York Application June 18, 1948,.Se'rial No: 33,847

1 1 Claim.

I iThetinventionrelates to; removable switchgear interlocking control andparticularly to interlocking; control for metal-enclosed removable self disconnecting;circuit breakershaving position-changing mechanism :for moving the circuit :breaker betweenuthes connected and the disconz-nected positions, providedcwith'zaremovable op- ;erating member.

Many metal-enclosed removable self-discon- ;;;-necting circuit breakers, particularly of "the drop-down powercircuit interrupting type-are To insure t'disconnecting or re-econnecting'the breaker while itlis closed. Most of the-circuit breakersof the drop-down type, particularly in the larger sizes,

rarely provided with jack screw elevating mechaznism that, can be either motor operatedor manually operated-to, raisethe breaker and hold it in its connected operating position on; the line.

The principal object of the present "invention .is-to provide "an improved "sequential multiple interlockmechanism operable under control'of ;the operating member so that it-will positively lock the removable self-disconnecting :circuit breaker in its operating connectedposition-upon dlsengagement' of the removable "operating mem- .ber as well :as prevent operation of the-circuit breaker position-changing mechanism unless the :breaker is first tripped openby the re-engage- :ment of the removable .operatingmember.

vThus the improved sequenti a1 multiple interlock mechanism upon removal of the operatingmember-; andi fol-freeing the circuit breaker for; reclo- "sureaautomatically insures against any creepage :of .thercircuit breaker:positionechanging;mecha- :nism" due to} arsor 'vibrations produced' :upon re gpeated closing and "opening r operations io'f athe breaker in "service on otherwise: such as mi ht cause thecircuit breaker" to become accidentally disconnected inservice "and also insures that the circuit breaker; 'isalways-tripped onen-Fbefcre the antivcreeplock is released guponi.the'-'re=engagement of the removable operating member with athe position-changing mechanism. Thus the removable operating=member-serves:as-the key-ele- ,ment in the improved sequential multiple locking-mechanism of the present nvent on and in thisway,additional security and safety in the interlocking control of the breaker is obtained.

vli'urther ob ects and advantages ofthe invent1on- Wl l-%Ppciarrintthe following.:,descr1ption cf the: accompanying :xdrawing in-which Fig.1 list-a :side elevation of a. typical metal-clad removable self -disconnecting circuit breaker provided with vthe improved :multiple interlocking .control 1 of the presentinvention;'Figi.2-is a partial sidexview of the improvedmultiple interlocking control. on an enlarged scale with certain partsbrokenaway to show more. clearlynthedetai'ls of construction; Fig-l 3ris=a .front view of.theinterlocking mechanism shown in-Fig...2 and Fig. is :a furtheren- .larged z-perspec-tive view indicating more clearly the cooperating. relationships of I :the removable operatin member with the several partsiof the improved-1 sequential multiple interlocking control mechanism.

As shown in Fig.- 1; the circuit breaker: 1 Q *is indicated raSvQf the air-blast "type although :the present invention is not in any way-limited to this type of circuit. breaker but-may be -used with advantage withtany type of removable selftdisconnecting'oil'onair circuit breaker. The removable circuit breaker I 0 (as shown :is provided withasupportingtrack or bar II on each side thereofiforw engagement by the opposite lifting channels l2 of the circuit breaker positionchanging or=elevating-mechanism indicated generally by thereference character 13. Each lifting channel I2 is movedbya pair ofeg ack screws l5 having suitable'thrust and'guide'bearings. l6 mounted on: the cross'members of the circuit :breakersupporting channel frame I1.

All of the jack screws l5aare simultaneously operated by means'of-therotatable driving member or shaft 20 thatisrotatablyisupported intthe 'box'frames' 18 and l9 and 'interc'onnectedby means of the beveled gearing 2| with the two jackscrews l5 shown and by means of the chain and'sprocket gearing 22 with. a similarbeveled gear shaftfor'operatingthe jack'screws on: the :oppositesideoi the breaker. Each jack screwfili r operates? a traveling "nut 27 'that is suitably seficuredtto'ona'of -theiliiting vchannels I 2. The "shaft. 29 is provided with anhexagonalend '23 ior engagement" by the socket head 24"df' are- -movable manual operating crank asshown 'in "Fi'gsfizandi' although the crank 24 may be applied to the" hexagonal end 'of i the stub shaft 25 that is connectedztozdrive' the operating 1 shaft: 2 ii throughthe poweram'plifying Jgearintgrzt" if :desired. Whileza i'rem'ovable manual 'cnverating "crank" 24 isshown'fin the drawing; it Willbe un- 'derstood that, if desired, removable meansrin the form of'a portableelectrio'drill or the like'may be provided "with asocket for-engaging with: the

shaft 2 to raise andilower-the breaker. JLImFigQIttheuremovableccirmzitcbreakerJ0 is shown in its elevated self-connected operating position wherein the terminal studs 30 of the circuit breaker engage with the connecting socket contacts 3| mounted inside of the insulating bushings 32. One of the socket contacts 3| is shown connected by the insulated conductor 33 with one of the busbars 34 located within the isolated busbar compartment 35 while the other socket contact 32 is shown connected by the insulated conductor 36 with a suitable current transformer 31 mounted inside the isolated load terminal compartment 38. Thus when the circuit breaker is lowered, the terminal studs 30 are automatically disconnected from the socket contacts 3| so that the entire breaker mechanism l may be lowered onto a dolly and bodily removed from the supporting frame I! for inspection, test, and maintenance.

It will be understood that the circuit breaker 8 is provided with suitable electric condition responsive automatic tripping mechanism, not shown. To insure safety in the removing and replacing operations, the circuit breaker It) also is provided with an interlock tripping member 40 carried on an extension of the breaker trip shaft 40' and biased by a spring 39 to a normally inactive position to be engaged by the cam plate 4| carried by the frame l4 and thereby moved to the tripping position so as to insure that the breaker is always tripped when it is raised into its connected operating position as shown in Fig. 1 by operation of the elevating mechanism |3. Thus the breaker is always open when the terminal studs 3|] are engaged with the sockets 3| and consequently the power circuit controlled by the breaker can be closed only by closure of the breaker itself.

To insure that the circuit breaker is always tripped before the elevating mechanism |3 can be manually operated to lower the breaker and disengage the terminal studs 30 from the sockets 3 I, a movable interlocking member 43 in the form of a box-like cover is pivotally mounted on the frame M on the pivot pin 44 so as to be movable into a tilted position as shown in Fig. i that effectively bars engagement of the removable crank 24 with the hexagonal end of either the operating shaft 2|! or the stub shaft 25. Consequently, before an operator can apply the crank 24, the interlock member 43 must be moved from its tilted blocking position as shown by the dotted lines in Fig. 2 to which it is biased when the breaker is in the connected position both by gravity and by the spring 39 of the circuit breaker trip member 40 to its full-line position shown in Fig. 2. This can be done either by manually tilting the member 43 or more simply by using the removable crank 24 to tilt the member 43 until the ends of both the operating shaft 23 and the stub shaft project through the restricted opening 43' formed in interlock member 43 for engagement of the crank with the end of the shaft. Such engagement of the crank with the shaft forces the extension 45 of the interlock member 43 operates the circuit breaker tripp ng member 45 against the bias of spring 39 when the interlock member 43 is moved from its blocking position shown in dotted lines in Fig. 2 to its full-line position. Thus the'lnterlocking member 43 effectively insures that the elevating mechanism 3 can never be manually operated by the crank 24 to lower the breaker unless the breaker is first opening by operation of the breaker tripping member 40.

It will be observed, however, that the circuit breaker H] is supported in its connected operating position in which it is shown in Fig. 1 entirely by the jack screws l5. Consequently, under conditions of repeated jarring or continued vibration the jack screws l5 may creep enough so as to gradually lower the circuit breaker II] from its connected operating position in which it is shown in Fig. 1. In case such gradual creepage continues until the breaker tripping member engages with the cam plate 4| and trips the breaker, then serious inconvenience may result from such undesirable breaker operation.

In accordance with the present invention such accidental creepage of the elevating mechanism is effectively eliminated by means of a notched collar 48 fixed to the operating shaft 20 by the anchoring pin 49 and a latch 5n biased into engagement with the notches in the collar 48 to effectively lock the shaft 28 against any accidental rotation due to jars or vibrations. The latch 53 is pivotally mounted on the pin 5| carried by the bracket 52 that is bolted to the elevating mechanism cross frame l8 and is provided with a cam-shaped arm 53 having a finger 54 for engaging the end of the biasing spring 55 that biases the latch 58 into locking engagement with. a slot in collar 48 as indicated by the dotted lines in Fig. 2.

To retract the latch 58, the box-like movable interlock member 43 is provided with an upturned finger 56 that is carried into operating engagement with the cam-shaped arm 53 of the latch 5|] when the interlocking member 43 is moved to its full-line position shown in Fig. 2 in which the hexagonal end 23 of the operating shaft 20 becomes accessible through opening 43' for application of the socket 24 of the crank 24 thereto. When the crank 24 is thus applied to operate shaft 20, the socket 734' overlaps the edges of the restricted opening 43 formed in the interlock member 43 and hence serves to force the interlock member 43 to the position in which it is shown in full line in Fig. 2 so as both to maintain the latch out of locking engagement with the slotted collar 48 and the circuit breaker tripping member 48 in the tripping position. This permits the shaft to be turned to rotate the operating shaft 2|) so as to turn the jack screws |5 to lower the tripped circuit breaker from its connected operating position in which it is shown in Fig. 1 to the disconnected position or vice versa. Thus to effect a lowering or raising operation the removable operating member 24 must force the interlocking member 43 to perform the multiple interlocking functions of providing access to the operating shaft 28, maintaining the circuit breaker tripping member 48 in the tripping position, and maintaining the latch 58 out of locking engagement with the slotted collar 48. Upon disengagement of the removable operating member 24 after the circuit breaker is raised'to its connected po ition, the latch 53 is first returned into locking engagement with the slotted collar 4%.! and the interlocking member 43 is then returned to its bias position whereby the circuit breaker tripping member 4!] is returned to the non-tripping position.

What I claim as new and desire to secure by Letters Patent of the United States is:

In cembination. a circuit breaker positionchanging mechanism a rotatable drive shaft provided with an interlocking member comprising a slotted collar fixed thereto and rotatable therewith, a removable operating member engageable with one end of the shaft for 5 movingthe breaker between the connected and disconnected positions, a second interlock member hi 1 to a first position for yieldingly barring engagement of said removable operating member with the one end of the shaft and movable to a second position upon engagement therebetween, tripping means operated by said secondgrinterlock member in said second position for opening the breaker, and a movable latch havin biasing means for biasing the latch into ngagement with the first interlocking to prevent creepage of the positionmechanism while the operating member is d sengaged from the shaft and having means operated by the second interlock member in said second position thereof for releasing the latch.

CHARLES D. EICHELBERGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

